In the nursery, you state that Voldemort fired only two curses, both of which were a green light (the Killing Curse), & Lily only cast a protection spell on Harry. Consequently, no one in the room was hit with anything that would leave a physical injury (besides Harry somehow getting a scar from rebounding a curse), since Lily & Voldemort were both hit with the Killing Curse (or rebounded curse) & that curse leaves no physical marks of any kind. So the only blood that should be in the nursery are a bit in the crib from the scar on Harry's forehead, not several spots on the floor.

Nor should the room have several scorch marks on one wall since Lily's protection spell on Harry wouldn't have left any neither would the Killing Curses that Voldemort fired since the curses hit the targets (Lily, Harry, which then rebounded to hit Voldemort). Hagrid describes destruction which might suggest the magical backlash from the rebounded curse & destruction of Voldemort's body could have partially destroyed a bit of wall & roof (like the force from strong winds) but not scorch marks from spells.